Generally, in a rapid thermal processing (RTP) device, the most significant factor is a speed for heating up a substrate to a desired temperature. Also, the substrate should be uniformly heated. However, as the size of substrates is increasing, it becomes difficult to achieve the uniform heating. To overcome such a problem, there has been introduced an apparatus that horizontally rotates the substrate during the RTP.
In order to restrain generation of noise, vibration and particles, a maglev motor or a multipole-magnetized magnet has been adopted for the substrate rotating apparatus. However, in spite of trying various substrate rotating methods, ununiform heat overlapping sections 15a are inevitably generated as shown in FIG. 1. More specifically, since lights emitted from heating lamps 10 are overlapped, the heat overlapping sections 15a are generated in the annular form as the substrate 20 is rotated horizontally. When an oxide layer is grown on the substrate 20 with such an RTP device, thickness of an oxide layer 17a is increased along the annular heat overlapping sections 15a as shown in FIG. 1c. As a result, the oxide layer 17a is grown with ununiform thicknesses throughout.
Thus, mere horizontal rotation of the substrate is insufficient to prevent ununiform heating of the substrate.